The screeds on asphalt paving machines must be preheated to about 175.degree. F. to 200.degree. F. before paving commences to keep the hot asphalt from congealing on the sale face of the screeds. In the past, the preheating has been accomplished by oil or propane burners mounted on the moldboard and directly heating the top surface of the screeds. When using such burners, particular care must be taken to avoid overheating since this can result in permanent warping of the screed.
U.S. Pat. No. 4,818,140 discloses a screed extension which is slide-mounted on the moldboard of an asphalt paver of the floating screed type. The screed extension is divided into inner and outer screed sections which are hinged together so that the outer screed section can be swung upwardly relative to the inner screed section to engage and shape a sloping berm. Prior to the present invention, screed extensions have not been independently heated because the preheating system normally used for the main screed has not been considered to be adaptable for screed extensions.